PCI: Remove the deprecated "pci-dma-compat.h" API

Now that all usages of the functions defined in "pci-dma-compat.h" have
been removed, it is time to remove this file as well.

In order not to break builds, move the "#include <linux/dma-mapping.h>"
that was in "pci-dma-compat.h" into "include/linux/pci.h"

Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Acked-by: Bjorn Helgaas <bhelgaas@google.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>